Many electronic plumbing devices, such as faucets, have two basic modes of operation; the on-demand mode and the metered mode. In the on-demand mode, the electronics in the faucet sense the presence of a target in proximity to the faucet outlet, such as when a person's hands are placed under the faucet, and initiate the flow of water. Typically, the electronic faucet permits the flow of water for a preset time and then terminates the flow either at this preset time or when the user's hands are removed from under the faucet. In the metered mode, the faucet is turned on for a set time duration irrespective of how long the user's hands are under the faucet. However, neither of these modes is designed to periodically activate the faucet for a minimum flow or run time during normal use to flush out the water in the faucet to reduce or eliminate bacterial accumulation in the faucet, especially during infrequent use of the faucet. In addition, the time that the unit is activated in either of the common modes does not depend upon the minimum run time required to reduce bacteria.
Electronic faucets are in widespread use. Such faucets are preferred in many applications because of their water saving capabilities. Electronic faucets are also preferred in many health institutions and in public buildings because there is less likelihood of transfer of bacteria. This is because the users do not typically need to come in physical contact with faucet handles to activate the flow of water since electronic faucets are self-activating. In contrast, the handle or handles of a mechanical faucet are usually contacted by multiple users and can be a source of bacterial transfer between users.
However, electronic faucets typically have a larger volume or column of water between the outlet and the shut-off valve than mechanical faucets. This volume of water can become stagnant in infrequently used electronic faucets, or can become exposed to the air or to other sources of contamination, such as bacteria. For example, some sources have reported higher bacterial counts in the water column of some electronic faucets, as compared to mechanical faucets. Health institutions, such as hospitals, are especially sensitive to bacteria in faucets because it can potentially lead to more serious consequences. Because users of mechanical faucets tend to leave them running, especially during hand washing, mechanical faucets frequently have less bacteria in the water remaining in the faucet than electronic faucets.
There is therefore a need for an improved electronic faucet that is capable of reducing the amount of bacteria in the water remaining in the faucet. There is also a need to provide a minimum amount of water flow each time that the electronic faucet is activated. There is a further need to flush the water column with each activation. There is also a need to periodically activate an electronic faucet during extended periods of nonuse to discharge and to refresh the water retained in the water column of the faucet between the outlet and the shutoff valve.
Accordingly, it is a general object of the present invention to provide a new and improved electronic faucet with a periodically activated water flow with a means of providing a minimum amount of water and a minimum time that the faucet is activated to discharge any stagnant water remaining in the faucet, thereby reducing bacterial count in the faucet.
Another object of the present invention is to have a minimum amount of water flushed from the plumbing device with each activation.
Another object of the present invention is to provide a timer for timing the time in which the faucet is dormant so that the faucet may be periodically activated, such as after about 15 minutes to about 12 hours, and preferably about every four hours.
A further object of the present invention is to provide a minimum amount of time that the faucet remains on during the periodic activation, such as about 8 seconds.